/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2009 University of Washington

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifndef TAP_BRIDGE_H

#define TAP_BRIDGE_H

#include "ns3/net-device.h"

#include "ns3/mac48-address.h"

#include "ns3/nstime.h"

namespace ns3 {

class Node;

/**

 * \ingroup devices

 * \defgroup tap-bridge TapBridge

 * 

 * \brief A bridge to make it appear that a host is connected to an ns-3 net device.

 *

 * The Tap Bridge lives in a kind of a gray world somewhere between a Linux host and

 * an ns-3 bridge device.  From the Linux perspective, this code appears as the user

 * mode handler for a Tap net device.  That is, when the Linux host writes to the

 * /dev/tapx device that we create for it, the write is redirected into the TapBridge

 * and from that perspective, becomes a read.  The TapBridge then redirects the data

 * written (by the Linux host) to the tap device on out the ns-3 net device to which

 * we are bridged.  When a packet comes in from the ns-3 world to the ns-3 net device

 * we are bridging, it appears via a callback from that net device.  Our job is to

 * take those bits and write them back to the host using the user mode handler for

 * /dev/tapx.  This write to the device will then appear to the Linux host as if a 

 * packet has arrived on its device.

 *

 * The upshot is that the Tap Bridge appears to bridge a tap device on a Linux host 

 * in the "real world" to an ns-3 net device in the simulation.  In order to do this

 * we need a "ghost node" in the simulation to hold the bridged ns-3 net device and 

 * this Tap Bridge.  It won't actually do anything else in the simulation.  You will

 * be able to perform typical ns-3 operations on that node, but they will have no

 * effect other than to set up, tear down and configure the net devices and bridges

 * mentioned above.

 */

/**

 * \ingroup tap-bridge

 * \brief A bridge to make it appear that a host is connected to an ns-3 net device.

 */

class TapBridge : public NetDevice

{

public:

  static TypeId GetTypeId (void);

  TapBridge ();

  virtual ~TapBridge ();

  /** \brief Set the device to bridge.

   *

   * This method tells the bridge which ns-3 net device it should use to connect

   * the simulation side of the bridge.  

   *

   * \attention The ns-3 net device that is being set as the device must not 

   * have an IP address.  This address is a property of the host Linux device.

   */

  void SetBridgedDevice (Ptr<NetDevice> bridgedDevice);

  // inherited from NetDevice base class.

  virtual void SetName(const std::string name);

  virtual std::string GetName(void) const;

  virtual void SetIfIndex(const uint32_t index);

  virtual uint32_t GetIfIndex(void) const;

  virtual Ptr<Channel> GetChannel (void) const;

  virtual Address GetAddress (void) const;

  virtual bool SetMtu (const uint16_t mtu);

  virtual uint16_t GetMtu (void) const;

  virtual bool IsLinkUp (void) const;

  virtual void SetLinkChangeCallback (Callback<void> callback);

  virtual bool IsBroadcast (void) const;

  virtual Address GetBroadcast (void) const;

  virtual bool IsMulticast (void) const;

  virtual Address GetMulticast (Ipv4Address multicastGroup) const;

  virtual bool IsPointToPoint (void) const;

  virtual bool IsBridge (void) const;

  virtual bool Send (Ptr<Packet> packet, const Address& dest, uint16_t protocolNumber);

  virtual bool SendFrom (Ptr<Packet> packet, const Address& source, const Address& dest, uint16_t protocolNumber);

  virtual Ptr<Node> GetNode (void) const;

  virtual void SetNode (Ptr<Node> node);

  virtual bool NeedsArp (void) const;

  virtual void SetReceiveCallback (NetDevice::ReceiveCallback cb);

  virtual void SetPromiscReceiveCallback (NetDevice::PromiscReceiveCallback cb);

  virtual bool SupportsSendFrom () const;

  virtual Address GetMulticast (Ipv6Address addr) const;

protected:

  virtual void DoDispose (void);

  void ReceiveFromBridgedDevice (Ptr<NetDevice> device, Ptr<const Packet> packet, uint16_t protocol,

                                 Address const &src, Address const &dst, PacketType packetType);

private:

  NetDevice::ReceiveCallback m_rxCallback;

  NetDevice::PromiscReceiveCallback m_promiscRxCallback;

  Mac48Address m_address;

  Ptr<Node> m_node;

  std::string m_name;

  uint32_t m_ifIndex;

  uint16_t m_mtu;

  Ptr<NetDevice> m_bridgedDevice;

};

} // namespace ns3

#endif /* TAP_BRIDGE_H */